5 hp throttle control

#1
I have a hs50 fresh nos motor that I have on a bike that I finally am finishing up after swapping motors a few times, the motor runs great but only gives me full throttle when I first start it up and when its at a slow idle, if I jump on it and take off it only gives me about 2/3 throttle unless I reach down and open the throttle control wide open by hand and it takes off full power? I did change the intake to a slanted intake to put it on the bike, is my linkage from the governor causing my grief?
 

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#3
Sometimes the butterfly reaches full throttle before the hand grip, as you continue to twist the grip, the cable slips. I like to set the cable with the butterfly and grip at full throttle (without engine running) so the grip can't pull more than the butterfly can handle.
 

DaddyJohn

Well-Known Member
#4
Sometimes that tab can prevent the throttle plate from opening fully. You can trim/bend it appropriately if necessary.
 

markus

Well-Known Member
#5
Have you adjusted the governor at all? They will rev up but then kick the throttle back under load. If thats not the case and say it did not do that with the other intake on it, then you may have a binding linkage going from the arm to the throttle shaft, when running the vibrations may cause it to bind (Its usually the other way around but you never know) sometimes it helps to just put a little upward bend in that linkage about halfway between as the Z bend at the throttle shaft will bind a little. Other things to look are the travel limiter on the cable/throttle control mechanisim if its a later model engine, as it should not be there on a recreational spring return throttle setup. as seen here; throttle control hookup
 
#6
Have you adjusted the governor at all? They will rev up but then kick the throttle back under load. If thats not the case and say it did not do that with the other intake on it, then you may have a binding linkage going from the arm to the throttle shaft, when running the vibrations may cause it to bind (Its usually the other way around but you never know) sometimes it helps to just put a little upward bend in that linkage about halfway between as the Z bend at the throttle shaft will bind a little. Other things to look are the travel limiter on the cable/throttle control mechanisim if its a later model engine, as it should not be there on a recreational spring return throttle setup. as seen here; throttle control hookup
Mark this is the motor I got from you, nos that you freshened up with a lighting coil, I got it and put the slanted intake on and painted it up and just cannot seem to get it running correct, I have played with the governor linkage and thought I had it a few times but after a 100 yard ride it will act up either won't idle down or will not give me full throttle unless reach down and open the throttle control by hand, I know what you sent me was good to go, wants to run now with the choke 1/2 on? is it possible that I would need to adjust the governor ?
 

markus

Well-Known Member
#8
Mark this is the motor I got from you, nos that you freshened up with a lighting coil, I got it and put the slanted intake on and painted it up and just cannot seem to get it running correct, I have played with the governor linkage and thought I had it a few times but after a 100 yard ride it will act up either won't idle down or will not give me full throttle unless reach down and open the throttle control by hand, I know what you sent me was good to go, wants to run now with the choke 1/2 on? is it possible that I would need to adjust the governor ?
That really sounds alot like a bind or tension problem with the governor linkages. with changing it out to a slanted intake it may just have something slightly out of whack as the linkages end up sitting differently between the 2 styles. while I remember the engine, I dont remember the specifics of it offhand, I sell a lot of engines and that was a awhile back, so I dont know where the governor was set at. I would start from scratch though, and follow the book/instructions and put it to stock, and work your way back out to just out of kickback range (if that is what your looking for) while your doing that I would feel and watch for a bind of any type between arm and throttle shaft, as well as springback of the throttle shaft itself (it relies on that little spring on the shaft so that has to be in place and not stiff etc.).

Far as the 1/2 choke, that makes me think you may be getting some fuel contamination. I would pull the bowl trying to get the fuel thats in there into a clean container so you can carefully inspect it for debris or water droplets, etc... It doesn't take much.
 
#9
That really sounds alot like a bind or tension problem with the governor linkages. with changing it out to a slanted intake it may just have something slightly out of whack as the linkages end up sitting differently between the 2 styles. while I remember the engine, I dont remember the specifics of it offhand, I sell a lot of engines and that was a awhile back, so I dont know where the governor was set at. I would start from scratch though, and follow the book/instructions and put it to stock, and work your way back out to just out of kickback range (if that is what your looking for) while your doing that I would feel and watch for a bind of any type between arm and throttle shaft, as well as springback of the throttle shaft itself (it relies on that little spring on the shaft so that has to be in place and not stiff etc.).

Far as the 1/2 choke, that makes me think you may be getting some fuel contamination. I would pull the bowl trying to get the fuel thats in there into a clean container so you can carefully inspect it for debris or water droplets, etc... It doesn't take much.
will do thank you sir
 
#10
got it thanks for all the replies, had to adjust the governor, tweek the linkage and the bowl had debris in it , seems to be running pretty smooth at idle and wide open but have to wait for the rain to let off to run it and keep that 10 year old boy smile going, this is actually the first bike I picked up a year and a half ago and just now finishing after changing out the motors a few times and starting a half dozen other bikes and projects, thank you
 

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